Pyridyl ketipate lactones and derivatives in treating arthritis

ABSTRACT

Pyridyl ketipate lactones and derivatives having anti-arthritic activity prepared by alcoholysis of an appropriate pyridyl substituted dilactone.

United States Patent Sutton June 18, 1974 PYRIDYL KETIPATE LACTONES AND [56] References Cited DERIVATIVES IN TREATING ARTHRITIS UNITED STATES PATENTS lnventori Blaine Sutton, Hatboro, 3,321,484 5/1967 Krimmel 260/2955 3,373,169 3/1968 Cherdron et al 260/3439 [73] Asslgnee' 3,380,939 4/1968 Palm et al 260/9 Philadelphia, Pa.

[ Filedi p 8, 1972 Primary Examiner-Stanley J. Friedman [21] Appl' NOJ 287,381 Attorney, Agent, or FirmJoseph A. Marlino; Richard D. Foggio; William H. Edgerton Related US. Application Data [62] l;i7v;s4i01n7;fSer. No. l60,l90, July 6, 1971, Pat. No. ABSTRACT Pyridyl ketipate lactones and derivatives having anti- [52] US. Cl 424/266, 424/263 arthritic activity prepared by alcoholysis of an appro- [51] Int. Cl A6lk 27/00 priate pyridyl substituted dilactone.

[58] Field of Search 424/266 2 Claims, No Drawings PYRIDYL KETIPATE LACTONES AND DERIVATIVES IN TREATING ARTHRITIS This is a division of application Ser. No. 160,190 filed July 6, 1971 which has issued into US. Pat. No. 3,714,173.

This invention relates to novel lactones of ketipic acid and derivatives having valuable pharmacodynamic activity. More specifically these compounds possess anti-arthritic activity and at anti-arthritic doses they produce analgesic and antipyretic activity.

The compounds of this invention are represented by the following general structural formula:

wherein:

R represents methyl or ethyl; R, represents hydrogen, chlorine, bromine, fluorine, methyl, methoxy, ethoxy, dimethoxy, trimethoxy or trifluoromethyl;

R represents hydrogen, acrylyl, methacrylyl, dimethylacrylyl, crotonyl or cinnamoyl.

Preferably the compositions of this invention comprise a compound of Formula l above when R is methyl, R, is hydrogen, chlorine, bromine, methyl, methoxy or trifluoromethyl, and R represents hydrogen, acrylyl or cinnamoyl. Most advantageously R is methyl, R, is hydrogen, chlorine, fluorine or trifluoromethyl, and R is hydrogen.

The novel ketipate lactones and derivatives are prepared according to the following synthetic procedure.

(com) CH1CN ---r in which R, R, and R are as defined above for Formula 1. Thus a phenylacetonitrile is condensed with ethyl ox-.

alate in an alcoholic solution of an alkali metal lower alkoxide, such as sodium methoxide 0r ethoxide to give the ethyl 3-cyano-3-phenylpyruvate. This compound is further condensed with a pyridylacetonitrile in an alcoholic solution of an alkali metal lower alkoxide, such as sodium methoxide or ethoxide to yield the 2-phenyl-5- pyridyl-3,4-dioxoadiponitrile. The above condensations may also be carried out using a metal hydride, such as sodium hydride, in diglyme. The adiponitrile derivative is refluxed for a short period of time, for example, l or 2 hours, in an aqueous acid solution such as water/glacial acetic acid/concentrated sulfuric acid mixture and the resulting ketipic acid is refluxed with acetic anhydride to furnish the corresponding ketipic acid lactone of Formula 11 above. The dilactone is ring opened to the products of Formula I by brief refluxing in the appropriate alkanol, containing a mineral acid such as hydrochloric acid. The acid derivative is then heated with the appropriate acyl halide, preferably acyl chloride, to yield the desired unsaturated acyl esters. The reaction is advantageously carried out in a nonreactive organic solvent such as chloroform in the presence of pyridine. a I

The anti-arthritic activity of the compounds of this invention is measured by their ability to inhibit adjuvant arthritis in rats. The novel compounds of this invention produce marked inhibition of the development of adjuvant arthritis in rats at a daily oral dose of 25 mg. per kilogram of body weight. Adjuvant arthritis in rats is produced by a single injection of 0.75 mg. of Mycobacterium butyricum suspended in white paraffin (N.F.) into a hindpaw (left footpad). The injected paw becomes inflamed and reaches a maximum volume in 3-5 days (primary lesion). The animals exhibit a decrease in body weight gain during this initial period. Adjuvant arthritis (secondary phase) occurs after a delay of approximately 10 days and is characterized by inflammation of the non-injected sites (right hind leg), decrease in body weight gain and further increases in the volume of the injected hind leg. The compounds of Formula I administered in the doses described above beginning on the dayof adjuvant injection and continuing for 17 days thereafter, exclusive of days 4,5,1 1 and 12, protect the animals against development of both primary and secondary lesions of adjuvant arthritis.

The compounds of this invention may be administered orally or parenterally in conventional dosage unit forms such as tablets, capsules, injectables of the like, by incorporating the appropriate dose of a compound of Formula l, with carriers according to accepted phar maceutical practices. Preferably the compound is administered orally to an animal organism in a tablet or capsule comprising an amount sufficient to produce anti-arthritic activity. Each dosage unit will contain the active medicament in an amount of about 10 mg. to about 50 mg. Advantageously equal doses will be administered one to three times daily with the daily dosage regimen being about 10 mg. to about mg.

The pharmaceutical carrier employed may be, for example, either a solid or liquid. Exemplary of solid carriers are lactose, terra alba, sucrose, talc, gelatin, agar, pectin, acacia, magnesium stearate, stearic acid and the like. Exemplary of liquid carriers are syrup, peanut oil, olive oil, water and the like. Similarly the carrier or diluent can include any time delay material well known to the art, such as glyceryl monostearate or glyceryl distearate alone or with a wax.

A wide variety of pharmaceutical forms can be employed. Thus, if a solid carrier is used the preparation can be tableted, placed in a hard gelatin capsule in powder or pellet form, or in the form of a troche or lozenge. The amount'of solid carrier will vary widely but preferably will be about 25 mg. to about 1 g. If a liquid carrier is used, the preparation will be in the form of a syrup, emulsion, soft gelatin capsule, sterile injectable liquid such as an ampule, or an aqueous or nonaqueous liquid suspension.

The following examples are not limiting but are illustrative of compounds of this invention and the procedures for their preparation. Other variations of this invention will be obvious to those skilled in the art.

EXAMPLE 1 A mixture of 117.1 g. (1.0 m.) of phenylacetonitrile and 326 ml. (2.4 m.) of ethyl oxalate is added. to an ethanol solution of sodium ethoxide (prepared by dissolving 23.8 g., 1.08 g. atom ofsodium in 500ml. ofabsolute ethanol) and refluxed two hours. After cooling, diluting with 2,500 ml. of water and extracting with ether, the solution is acidified with acetic acid. The solid is removed and washed with water to give ethyl 3-cyano-3-phenylpyruvate, m.p. 127-129 C.

To a solution of 8.3 g. (0.07 m.) of 3-pyridylacetonitrile and 20 ml. of diglyme is added 10.0 g. of sodium hydride. Ethyl 3-cyano-3-phenylpyruvate 15.2 g. (0.07 m.) is added in portions at C. and the reaction mixture is stirred at room temperature overnight. The mixture is diluted with 500 ml. of water, extracted with ether, acidified with acetic acid, and liltered to yield 2-phenyl-5-( 3 -pyridyl )-3,4- dioxoadiponitrile.

A mixture of 14.0 g. (0.0484 m.) of 2-phenyl-5(3'- pyridyl-3,4-dioxoadiponitrile in 95 ml. of water, 140 ml. of glacial acetic acid and 70 ml. of concentrated sulfuric acid is refluxed for 1 hour. The suspension is cooled, poured onto 500 ml. of ice water and the solid removed and washed to give 2-phenyl-5-(3'-pyridyl) ketipic acid lactone 3,6.

2-Phenyl-5-(3'-pyridyl) ketipic acid lactone 3,6 5.0 g. (0.016 m.) is refluxed in 60 ml. of acetic anhydride for minutes. The cooled solution is poured into 300 ml. of methanol and 100 ml. of ice. The separated solid is dissolved in 100 ml. of methanol containing 5 g. of potassium hydroxide. The solution is acidified and diluted with water to yield methyl 2-phenyl-5-(3- pyridyl) ketipate lactone 3,6, m.p. 24S-245.5 C.

EXAMPLE 2 Acrylyl chloride, 5 ml., is added to a solution of 3.23 g. (.01 m.) of methyl 2-phenyl-5-(3-pyridyl) ketipate lactone 3,6 (as prepared in Example 1) in 25 ml. of chloroform containing 2 ml. of pyridine and refluxed for 5 minutes. The reaction mixture is then concentrated, washed and recrystallized to yield the 4-acryl ester of methyl 2-phenyl-5-(3-pyridyl) ketipate lactone 3,6.

EXAMPLE 3 Methacrylyl chloride 10 ml. is added to a solution of 6.46 g. of methyl 2-phenyl-5-(3'-pyridyl) ketipate lactone 3,6 (as prepared in Example 1) in 50 ml. of chloroform containing 2 m1. of pyridine and refluxed for 5 minutes. The reaction mixture is then concentrated, washed and recrystallized to yield the 4-methacrylyl ester of methyl 2-phenyl-S-(3'-pyridyl) ketipate lactone 3,6.

EXAMPLE 4 A solution containing 16.6 g. of cinnamoyl chloride, 3.26 g. of methyl 2-phenyl-5-(3-pyridyl) ketipate lactone 3,6 (as prepared in Example 1) and 25 ml. of chloroform containing 1 ml. of pyridine is refluxed for 5 minutes. The reaction mixture is concentrated, washed and recrystallized to yield the 4-cinnamoyl ester of methyl 2-phenyl-5-(3-pyridyl) ketipate lactone 3,6.

EXAMPLE 5 A mixture of 45.3 g. (0.31 m.) of pchlorophenylacetonitrile and 107 g. (0.72 m., 99 ml.) of diethyl oxalate in an alcoholic sodium ethylate solution (prepared by dissolving 7.13 g. [0.31 g. atom] of sodium in 120 ml. of absolute ethanol) is refluxed with stirring for 2 hours. The cooled reaction mixture is diluted with 700 ml. of water, acidified with acetic acid and cooled to ice bath temperature. The resulting solid is recrystallized from aqueous methanol to give ethyl 3-cyano-3- (p-chlorophenyl)-pyruvate, m.p. 134135 C.

Ethyl 3-cyano-3-(p-chlorophenyl)-pyruvate {40 g., 0.16 m.) and 3-pyridylacetonitrile 39.0 g. (0.33 m.) are added to an alcoholic solution of sodium ethylate (prepared from 7.36 g., {0.32 g. atom] of sodium and 190 ml. of absolute ethanol) and the resulting solution is refluxed for 2 hours. The reaction mixture is diluted with water, acidified with acetic acid and cooled to ice bath temperature to yield 2-(p-chloropheny1)-5-( 3- pyridyl)-3,4-dioxoadiponitrile.

A solution of 14.6 g. (0.4 m.) of 2-(p-chlorophenyl)- 5-(3'-pyridyl)-3,4-dioxoadiponitrile in a mixuture of 150 ml. of water. 210 ml. of acetic acid and ml. of concentrated sulfuric acid is stirred and refluxed for 2 hours. The reaction mixture is diluted with 500 ml. of water and cooled to ice bath temperature to yield 2-(pchlorophenyl)-5-(3-pyridyl) ketipic acid lactone (3,6).

3.67 g. (.01 m.) of 2-( p-chlorophenyl)-5-(3'-pyridyl) ketipic acid lactone 3,6 is refluxed in 60 ml. of acetic anhydride for 30 minutes and cooled. The mixture is poured into 300 ml. of methanol and 100 ml. of ice. The separated solid is dissolved in 100 ml. of methanol containing 5 g. of potassium hydroxide. The solution is acidified and diluted with water to yield methyl 2-(pchlorophenyl)-5-(3-pyridyl) ketipate lactone. 3,6.

EXAMPLE 6 Similarly be reacting Z-pyridylacetonitrile with ethyl 3-cyano-3-phenylpyruvate and following the subsequent synthetic steps as described in Example 1, there is prepared the product methyl 2-phenyl-5-( 2-pyridy1) ketipate lactone, 3,6.

EXAMPLE 7 10.0 g. of 2-phenyl-5-(3'-pyridyl) ketipic acid lactone 3,6 (as prepared in Example 1) is refluxed in ml. of acetic anhydride for 25 minutes. The cooled solution is poured into 500 m1. of ethanol and 700 ml. of ice. The separated solid is dissolved in 200 ml. of ethanol containing 8 g. of potassium hydroxide. The solution is acidified and diluted with water to yield ethyl 2-phenyl-5-(3-pyridyl) ketipate lactone 3,6.

EXAMPLE 8 EXAMPLE 9 Ingredients Mgfl'ablet Methyl 2-phenyl-5-(3'-pyridyl) ketipic acid lactone 3,6 25 Calcium sulfate, dihydratc 150 Sucrose 25 Starch l5 Talc 5 Stcuric Acid 3 The sucrose, calcium sulfate and methyl 2-phenyl-5- (3"-pyridyl) ketipic acid lactone 3,6 are thoroughly mixed and granulated with hot 10 percent gelatin solution. The wetted mass is passed through a No. 6 mesh screen directly onto drying trays. The granules are dried at 120 C. and passed through a No. mesh screen, mixed with the starch, talc and stearic acid, and

compressed into tablets.

EXAMPLE 10 Ingredients MgJCupSulc Ethyl 2-phcn '|-5-(T-pyridyl) ketipic acid lactone 3.6 50 Magnesium stearate 5 Lactose 350 The above ingredients are screened through a No. 40 mesh screen, mixed and filled into No. 0 hard gelatin capsules.

What is claimed is:

1. A pharmaceutical composition having antiarthritic activity in dosage unit form comprising a pharmaceutical carrier and from about 10 mg. to about 50 mg. of a chemical compound of the formula:

wherein:

R is methyl or ethyl;

R is hydrogen, chlorine, bromine, fluorine, methyl,

methoxy, ethoxy, dimethoxy, trimethoxy or trifluoromethyl; and

R is hydrogen, acrylyl, methacrylyl, dimethylacrylyl,

' crotonyl or cinnamoyl.

' 2. A method of producing anti-anthritic activity which comprises administering internally to animals in need of arthritic relief an amount sufficient to produce said activity a chemical compound of the formula:

wherein:

R is methyl or ethyl;

R, is hydrogen, chlorine, bromine, fluorine, methyl,

methoxy, ethoxy, dimethoxy, trimethoxy or trifluoromethyl; and

R is hydrogen, acrylyl, methacrylyl, dimethylacrylyl,

crotonyl or cinnamoyl. 

2. A method of producing anti-anthritic activity which comprises administering internally to animals in need of arthritic relief an amount sufficient to produce said activity a chemical compound of the formula: 